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Monday, April 21, 2008

Tutorial: How to Etch Copper

Etching metal is one of my favorite metalsmithing techniques- it's a great way to create a surface pattern or image in metal.If you want to give etching a try, I would recommend starting with copper. Copper is easy to work with and inexpensive, and copper etching solution is relatively safe to work with and also inexpensive.The basic principle of etching any metal is to apply a substance to the surface of the metal which will resist the bite of the etching solution. This substance is called resist. Once the resist is applied, all you have to do is submerge the piece in the etching solution and wait for it to etch.

Here are the materials you will need:-18 or 20 gauge copper-Scotch brite or steel wool-Masking tape-Resist- possible options include paint markers, nail polish, asphaltum varnish, press and peel film... For this tutorial I will show you the one I like to use- It's called stop-out varnish and it's basically a red tinted shellac. I got it from Dick Blick. Commenter Wolfgang pointed out that acrylic paint also works as a resist. (Thanks Wolfgang!)-Something to apply your resist with. I will show you how to apply resist with a nib pen but you can also use brushes.-Solvent- my stop-out varnish resist dissolves in rubbing alcohol. For other resists you will need acetone or mineral spirits.-Etching Solution- Ferric Chloride (also called PC board solution) you can get it from electronic supply companies, or from printmaking supply companies. I got mine from Dick Blick-A plastic tub-Rags-Rubber gloves-Cotton balls

Before we get started, I would like to take a minute to talk about safety issues. Ferric chloride etching solution is really quite safe to use. It is actually not an acid, but a salt. It only etches copper and brass. It can irritate your skin though, so wear rubber gloves. Also, ferric chloride is very staining. It will not come out of floors, clothes, etc and will take days to come off your skin so be careful!

Now here's the step by step:1. Prepare your metal.Resist sticks better on clean metal with a slightly rough surface, so give your copper a good rubbing with scotch brite or steel wool.2. Protect the back of the metal.I like to be extra careful so I start by painting a thin layer of resist over the back of the copper, then when it dries I cover it with masking tape. Use an old brush to spread the resist, and clean it with rubbing alcohol when you are done.

3. Apply the design.I use a metal nib pen to draw the resist onto the copper. I just fill a little cup with the resist, dip my pen in and draw it on. It's a little thicker than ink, so it takes a little getting used to. As you are drawing the design, the resist will start to dry and gum up the pen. I keep a little cup of rubbing alcohol handy, and when the resist starts to dry on the pen, I dip it in the alcohol and wipe it clean on an old rag.I've used a sharpie to mark out the borders of my designs. Sharpie is sort of a weak resist itself, so it may leave a faint mark on your etched metal. I'm cutting the pieces out where the sharpie lines are anyway so I'm not worried about it.This resist dries really fast, so just let it dry for 15 minutes or so and it is ready to go in the etching bath.

4. Etch the metal.Pour your etching solution into the plastic tub. I like to use a big plastic container with a lid, because I can just put on the lid to store the solution.When using ferric chloride, the copper needs to be suspended design side down in the etching bath. To do this, I just put a long strip of tape across the back of the piece, then place it in the etching bath just below the surface, with the ends of the tape attached to either side of the tub.Depending on how deep an etch you want and how fresh your solution is, etching can take half an hour to three or four hours. Just be sure to check the piece every so often. Just pick up one end of the tape and lift the piece out of the bath. It helps to give the surface of the copper a little rinse with water once in a while too.

5. Remove the resist.Once you have a deep enough etch on your copper, remove it from the etching bath, take it to the sink and rinse it off. Take a cotton ball and saturate it with rubbing alcohol and rub off the resist. Once the resist is off, it's a good idea to scrub the copper with some soap and scotch brite. Sometimes the residue of the etching solution will continue to etch the metal even after you remove it from the etching bath. To prevent this, you can scrub the metal with ammonia to neutralize the etching solution. (Thank again, Wolfgang) If you have a torch, I would recommend annealing and pickling the copper just to make sure it's completely clean.You now have an etched piece of copper that is ready to be cut, formed, and finished in any way you like.

copperheart- thanks so much for sharing- gave me a little refresher. Takes me back to the college days when I had access to an alloys studio and printmaking studio. I love your copper pendants (and all your work of course) They are stunning little beauties! :)

you have some wonderful tutorials on your blog! I use to etch metal the same way you described above, but I always wondered if there was a way to use a stamp or easier way to do an intricate design without freehanding it... thoughts?

Hi Courtney!One great way to transfer designs to metal for etching is to use press and peel film. It's a blue plastic film you can print with a laser printer or xerox machine. You heat up your metal on a hotplate or hot iron and then place the film printed side down on the metal. Then you rub the film down with the back of a spoon or something similar. The printed parts of the film transfer to the metal making the resist. I know you can get it from thompson enamel, and probably some other places too.

Beautiful blog and very useful informations about enameling, thanks a lot! I'm from Slovenia - working with ACS and PMC, just reading Pam East Enameling on metal clay book. I have purchased cooper clay from UK and will try to enamel some pendants.

One question for you: I have this enamel kit for fine silver http://www.metalclaysupplystore.com/catalogs/catalog.asp Do you hink it will work with cooper?

I can't seem to get the link to work- but any enamels that work on fine silver should also work on copper. The only difference is that transparent colors will look different on copper than they do on silver. Good luck!

I have seen several tutorials on copper etching, but yours is far and away the clearest & easiest to under stand. You mention etching silver. What chemical do you use for that. Thanks again. I will definitely try this.

Thank you for the tut - I actually came by earlier this week but didn't have time to leave a comment. I'm looking forward to trying this , and am planning to involve my son for a fun 'summer science project' lol.

Thanks guys... For etching silver you can use either diluted nitric acid of ferric nitrate. Ferric Nitrate is safer but doesn't seem to work quite as well. I havn't quite worked all the bugs out out my silver etching process yet, but maybe I will have a tutorial on that in the future.

Yes actually there are a few traditional enameling techniques that involve enameling on etched metal. One is to fill in the etched areas with enamel (champleve) and the other is to sift transparent enamel over the etched metal (basse taille). Maybe I'll do some tutorials on those in the future.

thank you for the information!I noticed, that the etching process sometimes continues, even after rinsing with water. I read, you should clean with ammonia. what do you think about this?Another question: Can you use acrylic paint as a resist?

Good point, Wolfgang. Cleaning the metal with ammonia is a good way to stop the etching process. I normally heat the metal and pickle to remove all the residue, but Ammonia is the best thing to use especially for people using cold working techniques.

Thanks so much for sharing this tutorial! I tried this for the first time just the other day, using your tutorial, and everything turned out so beautifully...can't wait to try more! Do you know if there is a way that you can etch both sides of the metal, for a coin-like effect? Would you have to do them separately, one at a time, or could you just draw on both sides and throw it in the solution?

In theory you can etch both sides at once. The only trouble is how to suspend the piece in the solution, because if it is lying on the bottom of the bath it won't etch properly. If you could drill a hole and suspend it from a wire or something that would work. Otherwise, you can always etch one side, remove the resist, and then paint a resist over all of the previously etched side and etch again.

Hey everybody. I recently got a comment asking what resists I use for etching but I think I rejected it by accident! So if you're reading this, I have found two I especially like. One is the red stop-out varnish shown in this tutorial, which I get from Dick Blick, and the other is sharpie paint pen. The sharpie paint pen is quick and easy to use, but not quite as durable as the stop-out varnish. Stop out varnish needs to be removed with alcohol, but the sharpie paint pen you can usually rub off with some steel wool or scotch brite.

If you are still checking on this post. Great tutorial. I have tried etching before and your instructions are about the best I have seen. One question if you know, how long should a batch of the ferric chloride last. Sometimes I can etch many things, other times I do just a couple and it seems it has lost its etching capabilities. Any suggestions, also on a way to extend its life. Your response is appreciated.

I don't have a good estimate for how long it should last. It depends on so many variables like the size of the pieces, the depth of the etch, etc. I always use mine many many times before it loses its etching power. Usually you can tell when it is on its way out because the etching takes on a grainier texture. I've heard that adding some citric acid will prolong the life of the ferric chloride. I think they have it at thompson enamel. Making sure you keep it well covered and away from light couldn't hurt either.

Dick Blick has small sheets of it, but they seem really expensive. The project I want to do will involve 26 2"x3" sheets, which is 156 square inches. It seems like the most cost-effective thing to do would be to get a large sheet and cut it up myself.

Alternatively, Dick Blick has sheets of zinc that are a bit cheaper. If I go that route, do you know what solution I should use for etching?

Hi Morgan, try Rio Grande or Monsterslayer for your copper. You should be able to get a 6 by 12" piece of 18 ga copper for around 13 dollars. If you can go thinner it would be even cheaper. As for zinc, I've never tried it so I'm not sure what you would use.

Great art! Great tutorials! Can't wait to read your new illustrated book on metalsmithing!! (I and so many others wish...) Have done a little copper etching and use baking soda to stop acid after ammonia knocked my sox off. Also found a link for zinc, steel and aluminum etching with salt water at www.nontoxicprint.com/thenewetchingchemistry.htm Hope this helps!

You can re-use ferric chloride many many times. It depends on the size of your pieces and how long you etch them for, but you will know it is starting to wear out because it will start taking longer to etch. As for disposal, you need to contact your local waste management department and ask them what you should do. They may want you to collect the solution and drop it off at the hazardous waste collection site.

Yes, you should be able to do that without too much trouble. You'll want a good resist that can stand up to a longer time in the bath. If you're etching really deep remember that the sides of the raised areas will be exposed to the chemical as well. With a really long etch the raised areas can be undercut by the etching chemical and lift off.

Hi AlisonI am currently studying a B-tech level 3 national diploma in Jewellery Desgin at Manchester England, We are doing etching at the moment and i have purchased so Ferric chloride to try at home , I was wondering if you can Etch silver with ferric chloride , your tutorials are great and your jewellery is amazing.Susan x

Hi Susan, For silver you'll need Ferric Chloride. You use it the same way but it comes in a dry crystal form and you mix it with water. You can get it from a scientific chemical supply company. You can also use nitric acid but it is a lot nastier.

Thanks so much for this! I'm excited to try it.One question - how do you cut your pieces, and get them perfectly circular?I'm thinking if it requires a pricey cutter, I just might get pre-cut discs.Thank You!!

Thank-you so much for producing this tutorial! I teach advanced art techniques to gifted students, and this is going on our to-do list this year! Oh, and one funny thing, I had some scrap copper flashing .001, (the aluminum foil of copper sheeting), and when I put it in the bath for 2 hours it ate everything that was not the resisted! Opps. But I am reminded of my in-class mantra- "there are no mistakes in art", I now have the neatest, thin line copper "drawing" ever! I found a great tutorial online that could help me understand copper foil thicknesses- http://basiccopper.com/thicknessguide.html

After reading your tutorial I decided to try this. I used braso and steel wool (SOS pad). I think stamped an image with staz on. I put my brass piece into the FErric Cloride and left it for over 2 hours. When i removed it nothing has happened. Doyou think it is the wrong abrasive or maybe my metal isn't actually brass or copper.Any suggestions?

Zebra-I'm guessing that brasso leaves a protective layer on the metal, which in this case is protecting your metal from the ferric chloride and preventing etching. Try using just dish soap and a scrubbie and see if that works better.

littlecherryhill- first of all, I love that you call them "Jesus Rays" that's exactly what they look like! I find that I get those most often with fresh etching solution when the etching is going very quickly, so I guess the trick would be to try to slow down the etching a bit. Maybe try diluting the etching solution with water, and if you are using any means to speed the process (heat or agitation) try it without. Otherwise you could try electrolytic etching which doesn't seem to produce those lines. Good luck!

I just found your blog-your so kind to respond in detail to everyone. I have made some low relief copper plates and want to try the your technique but the pieces are 7"x"10" and 6"x6". Do you think the resist will work on this larger surface? I purchased the press and peel blue sheets but they required an iron and my plates have a raised edge so there is no way Im going to be able to use an iron!Sincerely,Lauraartprofarc@sbcglobal.net

Laura- The only work-around I can think of for applying the press n peel film on the plates is to heat them up on a hotplate rather than an iron. Otherwise, any of the resists that are applied by hand would work fine. The red shellac based resist shown in the tutorial would work, or you could try a deco-color paint pen, which also gives very good results. Good luck!

Love the tutorial. I will be trying this after the holidays. I also design my handcrafted jewelry. I need some new "thing" to learn and this seems to be so interesting and quite beautiful. I love to draw too so this really gives me creative freedom. I also like the way you circled your patterns first on the sheet of copper. I would have first cut my discs then add my pattern. Now, I'm on my way to join your fanpage.